1. Field of the Invention
The present invention relates to a method for continuously rolling billets and an apparatus therefor.
2. Description of the Related Arts
A Conventional method of continuous rolling aiming at the manufacture of wires, rods, or shape steels at a high efficiency and with decreased energy comprises the steps of: discharging billets one at a time from the heating furnace, welding the rear end of preceding billet with the front end of succeeding billet using a single travelling flash-butt welding machine, removing the burrs at the welded portion using a scarfer or the like, heating thus prepared continuous billet to a specified temperature necessary for rolling in an induction heating unit, then continuously rolling the continuous billet in a rolling mill line. (For example, unexamined Japanese patent publication No. 52-43754 discloses the conventional method.) In a hot direct-rolling process (HDR process) same line, the billets are all directly sent from a continuous casting machine are continuously rolled by a single travelling flash-butt welding machine. (For example, examined Japanese patent publication No. 57-11722 discloses this method.)
In the billet continuous rolling process, the shortening of cycle time for treating a single billet is a critical variable. The weight of a single billet usually used is in a range of from 0.5 to 2 tons. To increase the production capacity to a level ranging from 70 to 80 ton/hour or more, the necessary cycle time for processing a single billet is 1 min. or less.
Conventional continuous rolling processes, however, use only one travelling welder on the manufacturing line. Since further shortening of welding time for treating a billet inherent to a travelling welder is difficult, the realization of a cycle time of 1 min. or less is impossible using conventional methods.